Platen guard for listing adding machine



Sept. 24, 195-7 Filed Aug. 2, 1954 H. J. CHALL ETAL PLATEN GUARD FOR LISTING ADDING MACHINE 2 Sheets-Sheet i Sept. 1957 H. J. CHALL ETAL 2,807,348

PLATEN GUARD FOR LISTING ADDING MACHINE Filed Aug. 2, 1954 2 Sheets-Sheet 2 Unitd t tes rr PLATEN GUARD FOR LISTING ADDING MACHINE Harold J. Chall, San Leandro, and Charles S Balaz,

Hayward, Calif, assignors to Friden Calculating Machine Co., Inc., a corporation of California Application August 2, 1954, Serial No. 447,312

6 Claims. (Cl. 197-143) This invention relates to improvements in listing adding machines and particularly to a platen guardfor such a machine.

It is among the objects of the invention to provide in a business machine, such as a listing adding machine having a rotatable platen and a paper printing tape extending partly around the platen, a platen guard which guides the paper tape past the platen and prevents the end portions of the tape from being accidently wound around the platen; which provides a firm, flat backing for the paper tape above the platen so that annotations may be written on the'pr-inting tape, if desired; which is firmly but detachably mounted on the machine frame in position such that it does not interfere in any way with threading the paper tape past the platen; and which is of sturdy and light weight construction and enhances the appearance of a machine to which it is applied.

Other objects and advantages will become apparent from a consideration of the following description and the appended claims in conjunction with the accompanying drawings wherein:

Fig. 1 is a perspective view of an adding machine platen and a platen guard illustrative of the invention;

Fig. 2 is an end elevational view of the platen, platen guard and associated print wheel assembly;

Fig. 3 is a front elevational view of the platen and platen guard with a portion of the platen broken away and shown in cross section to better illustrate the construction thereof; and

Fig. 4 is a transverse cross-sectional view on the line 4-4 of Fig. 3 with a fragmentary portion of the machine cover shown in-cross section.

With continued reference to the drawings, the numeral generally indicates the platen supporting portion of the frame of a business machine, such as the listing adding machine disclosed in application Serial Number 407,016, filed January 29, 1954 by Harold J. Chall for Calculating Machine, and the numeral 11 generally indicatesjthe printing platen assembly rotatably mounted in the frame The platen assembly 11 includes a shaft 12 journalled in spaced-apart, frame-carried bearings 13 and 14, and a platen of cylindrical shape mounted on the shaft between the bearings 13 and 14; The platen comprises a hollow core 15 of a suitable material, such as wood, metal inserts, as indicated at 16, press-fitted into the bore of the core 15 one at each end of the core and provided with coaxial bores receiving the shaft 12, a cover 17 of elastic material, such as rubber, enclosing the core 15 and end plates 18 and 19 disposed one at each end of the platen against the corresponding ends of the core 15 and formed integrally with or rigidly secured to the inserts 16. The end plates 18 and 19 have a diameter which is somewhat less than the outside diameter of the platen cover 17 so that the platen is provided at its ends with'terminal recesses 20 and 21 of annular shape coaxial with the rotational axis of the platen.

Flat brackets 24 and 25 are rigidly mounted on the machine frame, one at each end of the platen 11, by suitable means, such as the screws 26, and each of these brackets has a resilient tongue formation, as indicated at 27 and 28, formed of fiat metal stock integrally with the corresponding brackets and overlying the ends of the front portion of the platen 11 in bridging relationship to the annular terminal recesses 20 and 21, respectively, to guide a paper printing tape 29 around the front portion of the platen and hold the paper in contact with the front portion of the platen surface. It will be noted that the upper ends of the tongues 27 and 28 are connected to the corresponding brackets 24 and 25 so that the portions of the tongues below the upper ends thereof are resiliently free of the brackets and that the lower ends of the tongues are bent outwardly or forwardly to facilitate inserting the end of the paper tape 29 between the surface of the platen cover 17 and the tape retaining tongues 27 and 28.

Printing mechanism, generally indicated at 30, is disposed in front of the platen assembly 11 in spaced relationship to the platen surface and includes a series of ordinally arranged print wheels 31 which are movable toward the platen during the printing action of the machine to impinge the type characters 32 carried by the print wheels against the portion of the printing tape 29 held against the front portion of the platen surface by the tape guide tongues 27 and 28 of the brackets 24 and 25.

At their upper ends the brackets 24 and 25 are provided with projecting extension formations 34 and 35, respectively, and the extension 34 is provided with a pair of spaced-apart slots 36 and 37 while the extension 35 is provided with a pair of corresponding, spaced-apart slots 38 and 39. A tear bar 40, of elongated, rectangular shape and preferably formed of a suitable transparent material, such as a synthetic resin, is disposed above the upper portion of the platen and extends longitudinally of the platen with terminal tongues thereof fitted into the bracket slots 37 and 39 to secure the tear bar in position relative to the platen. The brackets are formed of material of suflicient resiliency that the tear bar can be disposed between the brackets and its terminal tongues inserted in the upper bracket slots without loosening the screws 26 or removing either of the brackets from the machine frame and the tear bar is provided at its rearward side with a beveled edge formation 42 against which the paper tape 29 can be torn straight across when it is desired to remove a printed portion of the tape from the machine.

The present invention is primarily concerned with a platen guard, generally indicated at 44, and preferably formed of flat sheet stock of a suitable material having high structural strength and rigidity, such as metal or synthetic resin plastic. This guard 44 is of generally rectangular shape and has a length somewhat greater than the length of the platen and a Width which is within the discretion of the designer but, in the example illustrated, is in the order .of the radial dimension of the platen. Arms 45 and 46 are disposed one at each end of the guard 44 and extend perpendicularly from one longitudinal'edge 47 of the guard, the corners of the guard at the ends of the other longitudinal edge thereof beingpreferably rounded off as is shown in Figs. 1 and 3. i 1

The distance between the inner or mutually opposed edges of the arms 45 and 46 is substantially the same as the length of the platen cover 17 so that, when the guard is operatively mounted on the machine, .as shown in the drawings, the outer end portions of the arms are disposed in the terminal annular recesses 20 and 21 of the platen assembly and overlie the peripheral surfaces of the end plates 18 and 19 somewhat below the end portions ofthe Patented Sept. .24, 1957 j 3 surface of the platen cover 17. The guard arms 45 and 46 are provided at their outer or distal ends with outwardly extending tongues 48 and 40 which fit into and fill the lower slots. 36 and 38, respectively, of the brackets 24 and 25.

The platen guard 44 can be assembled with and disassembled from the frame and bracket assembly by reason of the resiliency of the brackets but is supported by the brackets withsuflicient firmness and rigidity that the forward or upper surface of the body portion 52 of the guard can be used as a backing surface under the portion of the tape 29 immediately above the platen to enable a machine operator to write on that portion of the paper tape.

The portion of the guard adjacent the longitudinal edge 47 thereof is disposed below the rear, beveled edge 42 of the tear bar 40 and the guard extends upwardly and rearwardly from the rear edge of the tear bar 46 and the upper portion of the platen surface, as is shown in Fig. 2, at an angle to provide a convenient writing surface for the machine operator. The portion of the body 52 adjacent the longitudinal edge 47 and between the inner edges of the arms 45 and 46 is bent downwardly and beveled, as indicated at 54, so that it is substantially in contact with the adjacent portion of the platen surface and the outer or distal end portions of the arms 45 and 46 lie below the end portions of the platen surface and inwardly, relative to the rotational axis of the platen, of the undersurfaces of the resilient tongues 27 and 28. With this arrangement, when the end of a paper printing tape is threaded around the lower, forward portion of the platen and under the tongues 27 and 28, the end of the tape will ride over. the distal end portions of the guard arms 45 and 46 and over the body portion 52 of the guard and the guard will hold the adjacent portion of the printing tape away from the rear portion of the platen surface so that the end of the tape cannot be caught by the platen and wound around the platen, as frequently happens when a guard is not employed.

In Fig. 4 the tear strip 40 and platen guard 44 are shown as disposed within an opening 55 in the upper portion of the machine cover 56, the paper tape projecting through this opening and through the space between the rear beveled edge of the tear bar 40 and the front, lower edge of the platen body 52. After the end of the printing tape passes the rear edge of the guard 44, it is disposed at the outer side of the rear upper portion of the machine cover and cannot re-enter the opening 55 to wind around the platen.

The guard thus serves various useful functions, including providing a writing surface backing for the portion of the tape immediately beyond the beveled rear edge of the tear bar 40 and preventing undesirable winding of the tape around the platen and, if desired, the guard may be provided with a desired color or ornamentation so that it enhances the general appearance of the machine to which itis applied.

The invention may be embodied in other specific forms without departing from: the spirit or essential characteristics thereof. The present embodiment is, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

What is claimed is:

1. In a business machine having a frame, and a printing platen rotatably mounted in said frame for supporting a paper printing tape and having annular recesses one at eachend thereof, a flat platen guard extending longitudinally of and upwardly and rearwardly from said platen and having arm formations, one at each end thereof, received in the corresponding recesses in said platen to guide a paper printing tape past the platen and preclude the winding of the end portion of the tape around the platen, and means connecting said guard at the ends thereof to said frame.

In a business machine having a frame, and a printing platen rotatably mounted in said frame for supporting a paper printing tape and having annular recesses one at each end thereof, a fiat platen guard extending longitudinally of and upwardly and rearwardly from said platen and having arm formations, one at each end thereof, received in the corresponding recesses in said platen to guide a paper printing tape past the platen and preclude the winding of the end portion of the tape around the platen, and means connecting said guard at the ends thereof to said frame, said guard providing a flat backing for the portion of a printing tape immediately above the platen to facilitate the writing of annotations on the printing tape.

3. In combination with a business machine frame and a platen rotatably mounted in said frame and having annular recesses one at each end thereof, brackets mounted on said frame one at each end of said platen and each having a guide tongue bearing against the forward side of the platen at the corresponding end thereof and bridging the annular recess in the adjacent end portion of the platen to guide a paper printing tape partly around the platen and maintain the tape in contact with the platen surface, and a platen guard comprising a plate member of generally rectangular shape extending longitudinally of and outwardly from said platen and having arms extending substantially perpendicular from one longitudinal edge thereof and disposed one at each end of said guard, said arms being detachably connected to the corresponding brackets and disposed in the corresponding annular recesses in said platen to guide a paper printing tape past the platen.

4. In combination with a business machine frame and a platen rotatably mounted in said frame and having annular recesses one at each end thereof, brackets mounted on said frame one at each end of said platen and each having a guide tongue bearing against the forward side of the platen at the corresponding end thereof and bridging the annular recess in the adjacent end portion of the platen to guide a paper printing tape partly around the platen and maintain the tape in contact with the platen surface, and a platen guard comprising a plate member of generally rectangular shape extending longitudinally of and outwardly from said platen and having arms extending substantially perpendicularly from one longitudinal edge thereof and disposed one at each end of said guard, said arms being detachably connected to the corresponding brackets and disposed in the corresponding annular recesses in said platen to guide a paper tape past the platen and said one longitudinal edge of said guard being beveled toward said platen to facilitate passing the end of a paper tape past said platen and said guard.

5. In combination with a business machine frame and a platen rotatably mounted in said frame and having annular recesses, one at each end thereof, brackets mounted on said frame, one at each end of said platen, and each having a guide tongue bearing against the forward side of the platen at the corresponding ends thereof and bridgin g the annular recesses in the adjacent end portions of the platen to guide a paper printing tape partly around said platen, and a platen guard comprising a flat member of generally rectangular shape extending longitudinally of and outwardly from said platen and having arms extending substantially perpendicularly from one longitudinal edge thereof and disposed one at each end of said guard, said arms being disposed in the corresponding annular recesses at the ends of said platen to guide a paper printing tape past the platen and being sufficiently rigid in structure and attached by said brackets to said frame with sufiicient rigidity to provide a support for writing on the portion of a printing tape extending over said guard.

6. In a business machine having a frame and a printing platen rotatably mounted on said frame for supporting a paper printing tape, a platen guard extending longitudinally of and upwardly and rearwardly from said platen and having arm formations, one at each end thereof, extending partially around the corresponding end portions of said platen to guide a paper printing tape past the platen, and means connecting said guard at the ends thereof to said frame to rigidly support said platen guard from said frame.

References Cited in the file of this patent UNITED STATES PATENTS Mottram July 7, 1936 

